Locking device



v Patented Mar. 24, 1936 UNITED STATES PATENT OFFICE Wilcox-Rich Corporation, a corporation of Michigan Application July 5, 1935, Serial No. 29,981

4 Claims.

This invention relates to locking devices for holding screw threaded parts in any desired predetermined position without the use of locking nuts or any other auxiliary device to hold the threaded parts in a desired predetermined adjustment. When locking nuts are employed, to hold threaded parts in predetermined adjustment; such as, in valve mechanism for internal combustion engines, it is necessary to use three wrenches on certain types of mechanisms. Inaccurate adjustments are often made due to the troublesome handling of so many tools and the movement of the threaded parts when the lock nut is tightened, because of the tendency of a threaded part to move in the direction of the lock nut.

The present invention is adaptable for any use wherein it is necessary to lock threaded parts in any predetermined position, and is particularly adaptable to valve mechanisms, brake rods, slack adjusters, turnbuckles, etc., as there is no locking nut or any .other auxiliary device to hold the -i threaded parts in predetermined position. The threaded parts are so designed that the internal or external threads thereof are in contact at the side of the thread where thepressure in operation will force the threads together.

The invention further consists in the novel manner of constructing the parts and the arrangement of the threads thereof, so that when the parts are joined together, a frictional locking engagement is provided with the threads of the members suicient to hold the members together in their adjusted relation regardless of the amount of shock or vibration transmitted thereto.

The invention consists of certain novel features of construction and combinations of parts which will be hereinafter described and set forth in the appended claims.

In the accompanying drawings:

Fig. 1 is a view in elevation and parly in section showing the invention with the parts in locked position;

Fig. 2 is a vertical'section through one of the members;

Fig. 3 is a bottom plan view thereof;

Figs. 4, 5, and 6 are views in vertical section illustrating the manner in which the members are assembled; and

Fig. 7 is a vertical sectional view of a modied form of the member shown in Fig. 2.

In the drawings. the invention is disclosed in connection with a valve tappet, but it is not the intent to be limited to this particular disclosure, as it is evident that the invention is capable of sass/uan application to many other uses where fine or nice adjustments must be procured, and the parts subjected to Vibrations and shocks which would ordinarily cause the parts to work loose or become separated and defeat the very purpose for 5 which the adjustment has been made.

'I'he member I0 is preferably hollow or tubular, and provided with internal crew threads I I. One end of the member is provided with an enlarged head I2 against which a cam operates when the l0 device is employed for a valve tappet. The other or male member I3 consists of a stem provided with a head I4 which may engage a valve stem or rocker arm (not shown).

The member I3 is provided with two threaded 15 sections I5 and IB, the threads of which are of the same pitch, and adapted to have a screwthreaded fit with the threads Il of the member I0. 'Ihe threads of section I5 of the member I3 and the threads of section I6 are interrupted by 20 a mismatched lead,`that is, the rib of the threads of sections I5 and I6 are not a true continuation or in alinement with respect to each other. 'I'he dotted line I1 of Fig. 2 indicates a continuation of the thread of section I5, throughout the 25 length of stem I3 and onto the lower section I6, while the full lines indicate the oiset relation of the thread of section I6 with respect to the threads of section I5. a

It is to be noted that the member I3, as shown 30 in Fig. 2, discloses the threaded sections I5 and IB as being separated by a space I9 with each section in itself having the same or standard pitch. Assuming, as indicated by the dotted line I l, that the threads of the section I5 continue 35 throughout the length of the member I3 and a measurement was taken of the pitch between the threads of the section I5 with respect to the pitch of the threads of the section I6, the pitch between the threads of the. sections I5 and I6 40 would be shorter than the pitch of either of the threads oi section I5 or I6. The shortened pitch or lead between the sections I5 and I6 may be changed to any amount sufficient to give the required thrust to the thread. This thrust causes 45 section I6 to pull downwardly on section I5 as they are screwed into the member I0, causing section I5 to be. frictionally held in any predetermined position. The threads I5 of the member I3 are therefore axially displaced with respect to 50 the thread I6, thereby producing an interrupted lead between the two sections I5 and I6.`

The lower portion of the member I3 is bifurcated as at I8, so that the end is bifurcated in two directions with the bifurcations intersect- 'duce an annular recess I9 between the two threaded sections I5 and I6, which together with the bifurcations I8 provide the desired resiliency to the lower end of this member I3 to permit of the two threaded sections being attached to the tubular member I0.' In Fig. 1 the lower end of the member I3 is shown cored with the walls bifurcated or slotted at I8.

As illustrated in Figs. 4, 5, and 6 which show the method of assembly of the two members, the lower portion I6 of the male member I3 is screwed into the tubular member I0.- Then, as the threaded portion I5 takes into the threads II` of the tubular member I0, as indicated in Fig. 5, the lower section I6 will be caused to contract, which is permissible due to its bifurcation, thereby permitting the threads of the section I5 to engage and screw into the internal threads II of the tubular member I0. Due to the lack of continuance between the ribs of the threads of the sections I5 and IB, the threads of the section I6 will impinge against the upper face of the threads II of the tubular member I0, while the threads of section I5 will impinge against the lower face of the threads II of the tubular member I0, as shown in Fig. 1. This engagement of the threads of the tubular member with the threads of the two sections of the male member causes a locking of the male member in the tubular member, as the threads of the lower member I6 are exerting a tensional pull downward on the threads of the section I5, and thereby frictionally locking the member I3 and the member I0 to the desired adjustment. V

The amount of offset or interruption of the threads of the sections I5 andA I6 is governed by the degree of thrust and tension deemed necessary to be imparted to the threads in frictionally locking the two members together. The slots or bifurcations I8 and the reduced portion I9 permit the lower end of the stem or member I3 to contract or yield suiiiciently to compensate for a greater or lesser thrust on the threads as may be caused by too tight or loose a flt between the members.

Referring to Fig. 1, the adjusting screw or member I3 is shown in locked position, the locking of the screw I3 being accomplished by shortening the interrupted lead between the threaded sections I5 and I6. When the threaded member I3 is iitted to the mating member I0, the threads on section I6 thereof fit somewhat loosely, and as the threads of section l5 start to enter the threaded mating member Ill, as shown in Fig. 5, the lead of the screw being slightly shorter between the threaded sections I5 and I6, pulls the threaded section I5 downward and holds the threaded section I5 in tension. The slots I8 permit the section I6 to yield suii'iciently as the section I5 is screwed into the member I0, as otherwise the members II! and I3 would lock, or prevent the members from being screwed together without stripping the threads of one of the members.

, In Fig. 'I is illustrated a modified arrangement of the stem or member I3, wherein the transverse slots 20, extending from opposite walls of the member are substituted for the vertical slots In the manufacture of the threaded member I3, a good grade of material that retains itsv exibility and yields to compensate for the interrupted thread lead is desirable, as the yielding of the section I6, which is provided for by slotting the end of the screw or member I3, is for the purpose of providing the proper tensioning on the threaded section I5, as shown on the enlarged view of Fig. 1. Any desired amount of locking power can be obtained by controlling the amount the interrupted or mismatched lead is shortened between the sections I5 and I6 as shown by the dotted line I'I, as when a material is selected that will retain the resilient yielding portion, as shown in section I6 in Fig. 1, the holding power to retain the threaded members in xed position is permanently retained.

While it has been shown that the member I3 is provided with the two sets of threads I5 and Il, and which threads are interrupted, this same arrangement of threads could be applied to the member I0, and the member I3 provided with threads having the ribs thereof in uniform relation throughout the length of the member I3. Furthermore, the threads of the sections I5 and I6 could be so arranged thamhe threads I6 would exert a push on the threads I5 causing them to engage the upper face of the thread of the member I Il, and the threads of the section f I6 to engage the lower face of the threads, or just the opposite from the disclosure as shown in Fig. l.

It will be understood that the foregoing description only describes one use of the invention, and the same locking method may be applied to many uses where it is desired to retain threaded parts locked in predetermined position, and that other threaded devices may employ the invention without departing from the spirit and scope thereof.

What I claim is: 1

1. A locking device comprising two threaded interfitting members, one of said members being provided with two threaded sections, and the thread of one section being axially displaced with respect to the thread of the other section producing an interrupted lead between the sections, and yielding means on one of said members to compensate for the interrupted lead between said sections.

2. A locking device, comprising two screwuthreaded interfitting members, one of said members being provided with two threaded sections and having the thread of one section axially displaced with respect to the thread of the other section, so that the threads of one section will exert a tension on the threads of the other section as the member thereof is screwed to the other member for frictionally locking the two members together and means for allowing said member provided with the two threaded sections to yield sufficiently to compensate for the thrust on the threads thereof in connecting the members together.

3. A locking device, comprising two screwthreaded interiitting members, one of said members being provided with two threaded sections and having the thread of one section axially displaced with respect to the thread of the other section, so that the threads of one section will exert a tension on the threads on the other section as the member thereof is screwed to the other member for frictionally locking the two members together, said member having the two threaded sections being provided with slots to permit said member to yield as the members are connected together.

4. A locking device, comprising a. member having internal screw-threads, and another member provided with a plurality of threaded sections adapted to have screw-threaded engagement with the threads of the rst-named member, one of the threaded sections of the second-mentioned member lhaving the thread thereof axially displaced with respect to the thread'ot another section, said sectioned threaded member having slots therein to permit it to yield when the members are connected together and cause the threads of one section to exert a tension on the threads of another section to frictionally lock the members together at any adjustment therebetween.

HAROLD r. DYER; 

